What is the Difference Between HER2 and BRCA?

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HER2 and BRCA are two different genes associated with breast cancer. The key differences between them are:

  • Location and type of mutation: HER2 is a gene located on chromosome 17 in humans and undergoes somatic mutations, causing nonhereditary breast cancer. On the other hand, BRCA1 and BRCA2 (collectively referred to as BRCA) are two genes located on chromosomes 17 and 13, respectively, that undergo germline mutations, causing hereditary breast cancer.
  • Prevalence: About 20% of breast cancers are due to HER2 mutation, while about 5 to 10% of breast cancers are due to BRCA mutation.
  • Inheritance: HER2 mutations are not inherited, while BRCA mutations are inheritable and increase the risk of breast cancer in both the carrier and their relatives.
  • Cancer aggressiveness: Breast cancers with HER2-overexpression/amplification (HER2+) have a more aggressive natural history and are responsive to HER2-directed therapies. BRCA-associated breast cancers, especially those with BRCA1 mutations, have a higher likelihood of developing breast cancer in both breasts.
  • Co-occurrence: Limited data from case series suggest that cancers in women with BRCA mutations typically are not HER2-positive. In BRCA1 carriers, 5.4% of breast cancers were HER2-positive, compared to 9.5% in BRCA2-mutated patients.

In summary, HER2 and BRCA are two distinct genes associated with different types of breast cancer: HER2-mutated breast cancer is nonhereditary and affects about 20% of cases, while BRCA-mutated breast cancer is hereditary and accounts for 5-10% of cases. The aggressiveness and treatment of these cancers may vary based on the specific gene involved.

Comparative Table: HER2 vs BRCA

HER2 and BRCA are two different genes that play roles in the development of breast cancer. Here is a table highlighting the differences between them:

HER2 BRCA
HER2 is a gene present in chromosome 17 in humans. BRCA represents the two genes BRCA1 and BRCA2 present in chromosome 17 and 13, respectively, that undergo germline mutations to cause hereditary breast cancers.
HER2 mutations lead to about 20% of breast cancers. BRCA mutations lead to about 5 to 10% of breast cancers.
The prevalence of HER2 positivity among BRCA1/2 mutation carriers is poorly and variably described, ranging from 0% to 10% and 0% to 13% in BRCA1 and BRCA2 carriers, respectively. The prevalence of HER2 positivity among breast cancers in BRCA1/2 mutation carriers is poorly and variably described, ranging from 0% to 10% and 0% to 13% in BRCA1 and BRCA2 carriers, respectively.

HER2 undergoes somatic mutations to cause nonhereditary breast cancer, while BRCA undergoes germline mutations to cause hereditary breast cancer.